Fuses are sacrificial devices used in integrated circuits to provide overcurrent protection. When an excessive current is applied to a fuse structure such as a thin metal line, the fuse structure loses conductivity and an open circuit is formed. The amount of current required to form the open circuit depends at least in part on the cross-sectional area of the fuse structure. Fuse structures suitable for use with low program currents have smaller cross-sectional areas than fuses suitable for use with higher program currents. However, conventional fabrication methods produce fuse structures that are at least 20-30 nm wide.